10-degrees AFTER TDC at idle? Really?

I am still tuning these dual 34-PDSIT 2/3 carbs on my 2lt, 1979 (CJ Engine) bus.

I am working through this: http://www.itinerant-air-cooled.com/viewtopic.php?t=7767

And I get to the end of step 5 to discover that the recommendation is 10-degrees AFTER TDC at idle.

Is this correct? I have never seen anything ATDC on my bus.

Also .. on the diagrams he is showing vacuum advance and vacuum retard into the distributor. I only have one vacuum tube into the distributor.

 

I noticed that Haynes says "7 degrees BTDC" for European bus (which mine is) and "10-degrees ATDC" for US. So I am now thinking to ignore the timing advice section on these instructions.

 

Timing is decided what distributor you have

 

Just ignore it. Start with 7.5* static, then time it with a light for 28-30* max advance when revved.

 

USA thing could be smog control requirements?
Ignore

 

That Itinerant article is brilliant but it is geared to US buses so a bit of lateral thinking is occasionally called for. The ATDC timing thing is for dual vacuum distributors which I don't believe we're ever fitted to European buses as it was to get through ever tighter US emissions regs.
Time it to 7.5°BTDC as normal and check max advance doesn't go over 30° when the engine revs.

 

Also, best to avoid Colin's suggestions on wearing really tight shorts.

 

Probably the most important point of all

 

I don't think I have got to that bit yet. But suffice to say - any shorts are tight on me these days (and not in a good way )